1. Field of the Invention
The present invention relates to one or more embodiment of an organic light-emitting display apparatus.
2. Description of the Related Art
In general, a flat display device is largely classified into a light-emitting type and a light-receiving type. Light-emitting type display devices include flat cathode ray tubes, plasma display panels, electroluminescent display devices, light-emitting diode display devices, or the like. Light-receiving type display devices include liquid crystal displays (LCDS) or the like. Among these display devices, electroluminescent display devices have advantages such as wide viewing angles, excellent contrast, and rapid response speeds, thus drawing attention to the electroluminescent display device as a next-generation display apparatus. Electroluminescent display devices may be an organic electroluminescent device or an inorganic electroluminescent device (e.g., organic light emitting display devices) according to the material forming a light-emitting layer.
The organic electroluminescent device is a self-emission display which performs electrical excitation of an organic fluorescent compound and emits light. The organic electroluminescent device allows driving at a low voltage, facilitates preparation of a thin film, and provides wide viewing angles and rapid response speeds, thereby drawing attention as a next-generation display apparatus which may solve problems with an LCD.
The organic electroluminescent device includes a light-emitting layer, which is formed of an organic material, between an anode electrode and a cathode electrode. In the organic electroluminescent device, as a positive electrode voltage and a negative electrode voltage are respectively applied to the anode electrode and the cathode electrode, a hole injected from the anode electrode moves to the light-emitting layer via a hole transport layer (HTL) and an electron moves from the cathode electrode to the light-emitting layer via a electron transport layer (ETL). Thus, an electron and a hole recombine at the light-emitting layer to thus generate an exciton.
When the excitons are changed from an excitation state to a ground state, fluorescent molecules of the light-emitting layer emit light, thus forming an image. A full-color organic electroluminescent device is formed to include a pixel which displays three colors including red, green and blue, thereby implementing full colors.
In such an organic electroluminescent device, a pixel-defining layer is formed on both edges of the anode electrode. Then, a predetermined opening is formed in the pixel-defining layer, and a light-emitting layer and a cathode electrode are sequentially formed on a surface of the anode electrode which is exposed by the opening.